The advanced configuration and power interface (ACPI) describes industry standard interfaces for computer systems. In particular, ACPI involves the use of operating systems for directing configuration and power management of such computer systems.
Computer systems employing ACPI perform configuration and power management functions using ACPI code. Specifically, ACPI code is used to determine platform-specific information regarding the particular hardware and/or software, for example, of such a computer system. Once the configuration of the computer system has been determined, the ACPI code manages the power requirements of the various devices of the computer system.
ACPI code is stored in a portion of memory of a computer system known as ACPI namespace. An operating system of a computer system typically writes ACPI code into the ACPI namespace as a device tree, which identifies each of the devices of the computer system and associated functional routines for the identified devices.
In operation, the operating system evaluates the device tree to identify the devices of the computer system. Once a device is identified, the operating system attempts to associate or “attach” a driver to the device so that the device can operate properly.